I am of the belief that the college has everything it needs to make its decisions. Every applicant to a selective college will have accomplishments which occur after submission. AOs know that, but they don’t want to be inundated with minor updates from thousands of applicants.
So does that mean that one should not submit updates? No. That’s not what I’m saying. But one needs to be judicious. If it’s something that made the nationally-read papers (and not just the local free weekly) like an Academy Award nomination (or similar prestigious achievement), include on the update. If it’s to tell them that you were elected softball captain, had another 4.0 quarter (or anything at the school level Including MVP), don’t.